The most important piece of optional equipment (it really isn’t optional; every player should carry one) is a tape measure.

Strictly speaking, you don’t need a plastic throwing circle — you can always play the traditional way, by drawing the circle in the dirt. Nevertheless, a plastic throwing circle is very convenient. You can buy one, but it is easy to make one yourself.

A boule towel is also a convenient piece of equipment, for toweling off the dusty boules after the end of rounds. You can easily make your own from an old washcloth, towel, or the leg of an old pair of jeans.